Convection

Convection:

• Transfer of heat by actual motion of material.
• Eg : Hot air furnace, the hot water heating system and flow of blood in the body.
• Rate of transfer of heat in convection is directly proportion to the temperature difference between two parts of the convective fluid and to the surface area of the fluid exposed.
• Heat is transmitted only vertically upward.
• Faster than conduction but slower than radiation.
• $\frac{Q}{t}=hA\Delta \theta$

Application:

1. Room Ventilation (Warm air moves outside through the ventilators continuously keeping the room cool)
2. Trade winds (Convection current of air blows from north east towards the equator, which is called trade wind.)